Foreign secretary William Hague on the podium at the Conservative party's spring forum in Cardiff at the weekend. Photograph: Leon Neal/AFP/Getty Images

William Hague, the foreign secretary, approved the botched plan to send a team of armed diplomats and SAS soldiers into eastern Libya in an effort to build diplomatic contacts with anti-Gaddafi rebels.

The eight M16 officers and SAS soldiers were arrested then deported after only two days in the country.

The prime minister's official spokesman was reluctant to reveal details, partly due to the involvement of special forces, but told a briefing Hague had approved the operation "in the normal way".

It was impossible to discern from the briefing whether David Cameron had been specifically informed in advance, but it was stressed that the prime minister and the foreign secretary are in constant contact.

Hague will be asked by shadow foreign secretary Douglas Alexander in the Commons to explain more of the thinking behind his decision to send in SAS troops by helicopter.

Hague had already established phone contact with rebel leaders, including former interior minister Abdul Fattah Younis, raising questions as to why the British needed to operate in such a cloak and dagger way.

Senior officials had said on Friday that a diplomatic taskforce would go to Benghazi, the capital of the rebels, in due course. But in reality an advance guard had already been sent.

In an earlier statement Hague said: "The team went to Libya to initiate contacts with the opposition. They experienced difficulties."

Oliver Miles, the former British ambassador to Libya, described it as a farce.

Richard Northern, the current British ambassador to Libya, was called by rebels to explain what the group was doing in eastern Libya.

Northern quit Libya with the rest of the UK diplomatic team at the height of the fighting in Tripoli.

He spoke to a representative of the former justice minister Mustafa Abdel Jalil – who is now a rebel leader – to explain the men's mission.

A phone call between Northern and Jalil's spokesman was intercepted by the Gaddafi regime and excerpts were played on Libyan state TV on Sunday.

In that phone call Northern did not seem to be aware that the diplomatic mission would arrive by night in helicopters.

The Libyan state TV broadcast claimed to show the UK ambassador speaking to a rebel spokesman.

"They experienced difficulties, which have now been satisfactorily resolved. They have now left," Hague said.

"We continue to press for Gaddafi to step down and we will work with the international community to support the legitimate ambitions of the Libyan people."